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United States Patent | 5,613,200 |
Hamabe | March 18, 1997 |
Each of a plurality of base stations in a mobile radio communication system has a plurality of sectoral zones each having a directional antenna of horizontal directivity pattern. Radio channels are divided into as many groups as the number of sectoral zones per base station. The channel groups are assigned to the sectoral zones as the preferential allocation channel groups in such a manner that the same channel groups are assigned to the sectoral zones which have substantially the same directions determined by antenna directivity. When a request for communication occurs within a sectoral zone, channels are selected from the channel group assigned to the sectoral zone. If the carrier-to-interference power ratio of a selected channel is equal to or greater than a predetermined value, the selected channel is allocated. The mobile radio communication system thus has improved channel utilization efficiency to accommodate more traffic.
Inventors: | Hamabe; Kojiro (Tokyo, JP) |
Assignee: | NEC Corporation (Tokyo, JP) |
Appl. No.: | 487696 |
Filed: | June 7, 1995 |
Mar 17, 1993[JP] | 5-081101 |
Current U.S. Class: | 455/450; 455/62; 455/452.2 |
Intern'l Class: | H04Q 007/36 |
Field of Search: | 455/33.1,34.1,62,63,34.2,33.4,56.1 379/59,58 |
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5212830 | May., 1993 | Miller | 455/33. |
5233643 | Aug., 1993 | Naeini et al. | 455/34. |
5257398 | Oct., 1993 | Schaeffe | 455/33. |
5379447 | Jan., 1995 | Bonta et al. | 455/56. |
5437054 | Jul., 1995 | Rappaport et al. | 455/34. |
5448761 | Sep., 1995 | Ushirokawa | 455/62. |
Foreign Patent Documents | |||
0359535 | Mar., 1990 | EP. | |
0430173 | Jun., 1991 | EP. | |
0544095 | Jun., 1993 | EP. |
Nordic Seminar on Digital Land Mobile Radiocommunication, 5 Feb. 1985, pp. 209-217, Sternvall, "Calculation of the Capacity and Co-Channel Interference in a Cellular System". Bell System Technical Journal, vol. 62, No. 7, Sep. 1983, pp. 2037-2065, Sunberg, "Alternative Cell Configurations for Digital Mobile Radio Systems". 42nd Vehicular Technology Society Conference, vol. 1, 10 May 1992, pp. 37-42, Lee, "Efficiency of a New Microcell System". |